Cell separation compositions and methods

ABSTRACT

The invention provides compositions and methods for cell separation. These reagents and techniques specifically agglutinate cells via surface antigen recognition and can be used to recover even rare cell types in high yield.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Application Ser. No. 5 60/282,823, filed on Apr. 10, 2001.

TECHNICAL FIELD

[0002] The present invention relates to compositions and methods for separating cells.

BACKGROUND

[0003] Many conventional blood cell isolation procedures include a preliminary bulk separation of erythrocytic and granulocytic components by density-gradient sedimentation. Density-gradient separation relies on small differences in the density of different cell types causing them to segregate at different levels in a fluid medium of variable density. Differences in density between the cell types can be small, and individual cells types can be heterogeneous in size and density. Consequently, particular cell types can become distributed throughout a density-gradient medium rather than precisely segregating at a discrete area in the density medium. This phenomenon can result in poor recovery of desired cells and/or contamination with undesired cell types. In procedures that enrich for rare blood cell types such as hematopoietic progenitor cells, density-gradient sedimentation generally results in poor yields. For example, using conventional density-gradient methods to isolate progenitor cells (e.g., CD34+ hematopoietic stem cells) from umbilical cord blood reportedly results in a significant loss of the desired stem cells. See e.g., Wagner, J. E., Am J Ped Hematol Oncol 15:169 (1993). As another example, using conventional density-gradient methods to isolate lymphocytes reportedly results in selective loss of particular lymphocyte subsets. See e.g., Collins, D. P., J Immunol Methods 25 243:125 (2000).

[0004] Increasing the recovery of rare cell types from donor tissue could dramatically improve the success of transplant and immune therapies (e.g., bone marrow transplants, stem cell-based gene therapy, and immune cell therapy), the success of which apparently is related to the actual number of the cells being used for therapy.

SUMMARY

[0005] The invention provides compositions and methods for separating cells. The disclosed compositions and methods can be used, for example, to efficiently prepare cells for tissue culture, immunophenotypic characterization, other diagnostic testing, further purification, and therapeutic administration.

[0006] Methods of the invention involve for contacting a blood cell-containing sample (e.g., peripheral blood sample, umbilical cord sample, and bone marrow sample) with a cell separation composition. Without being bound by a particular mechanism, compositions of the invention can selectively agglutinate cells via interaction with cell surface antigens and/or by stimulating cell-cell adherence (e.g., via increased expression of cell surface adhesion factors). Agglutinated cells partition away from unagglutinated cells, which remain in solution. Cells can be recovered from either or both the agglutinate or the supernatant phase.

[0007] The disclosed compositions and methods can be used to isolate and enrich for a variety of cell types, including, for example, T lymphocytes, T helper cells, T suppressor cells, B cells, hematopoietic stem cells, circulating embryonic stem cells, circulating fetal cells in maternal circulation, and circulating metastatic tumor cells. The disclosed compositions and methods can be used in the context of allogenic and autologous transplantation. In the context of autologous transplantation, the disclosed compositions and methods can be used, for example, to remove undesired cells such as metastatic cancer cells from a patient's blood or bone marrow. Desirable cells (e.g., hematopoietic stem cells) then can be returned back to a patient without, or substantially free of, life-threatening tumor cells. The disclosed compositions and methods can be applied to cells of any mammal, including humans, non-human primates, rodents, swine, bovines and equines.

[0008] Cell separation compositions can contain dextran, anti-glycophorin A antibody, as well as antibodies against cell surface antigens such as CD9, CD15, CD2, CD3, CD4, CD8, CD72, CD16, CD41a, HLA Class I, HLA-DR, CD29, CD11a, CD11b, CD11c, CD19, CD20, CD23, CD39, CD40, CD43, CD44, CDw49d, CD53, CD54, CD62L, CD63, CD66, CD67, CD81, CD82, CD99, CD100, Leu-13, TPA-1, or surface Ig, and combinations thereof. Cell separation compositions can contain antibodies against surface antigens of other types of cells (e.g., cell surface proteins of tumor cells).

[0009] Antibodies against cell surface antigens can be included in a cell separation composition in either or both soluble and substrate-bound forms. Antibodies can be bound to substrates such as latex microparticles, acid-etched glass particles, aggregated polypeptides, polysaccharides, avidin particles, or biotinylated agarose gel particles. Antibodies in cell separation compositions can be monoclonal and can be IgM or IgG antibodies. In some embodiments, a cell separation contains antihuman antibody. The concentration of a soluble antibody in a cell separation composition can be about 0.1 mg/l to about 15 mg/l. Substrate-bound antibodies can be included in a cell separation composition at a concentration between about 0.1 and about 50.0×10⁹ particles/l.

[0010] Cell separation compositions also can contain heparin, divalent cations (e.g., Ca⁺², Mg⁺²), and phosphate buffered saline. In some embodiments, compositions have a pH between 6.8 to 7.8 (e.g., between 7.2 to 7.4).

[0011] The invention also provides kits containing components of a cell separation composition and packaging material. Kits can include a blood collection vessel such as a blood bag or a vacuum tube.

[0012] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0013] Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.

DETAILED DESCRIPTION

[0014] The invention features compositions and methods for separating cells. Compositions of the invention can be used to selectively agglutinate cells from blood cell-containing samples. Without being bound by a particular mechanism, compositions of the invention can agglutinate cells via interaction with cell surface antigens and/or by stimulating expression of cell surface adhesion factors such as LFA-1 (Lymphocyte Function-Associated Antigen-1, CD11a/CD18) and ICAM-1 (Intercellular Adhesion Molecule-1, CD54). Agglutinated cells partition away from unagglutinated cells, which remain in solution. Cells can be recovered from the supernatant or from the agglutinate.

[0015] Cell Separation Compositions

[0016] A cell separation composition in accord with the invention can contain dextran and one or more antibodies against (i.e., that have specific binding affinity for) a cell surface antigen.

[0017] Dextran is a polysaccharide consisting of glucose units linked predominantly in alpha (1 to 6) mode. Dextran can cause stacking of erythrocytes (i.e., rouleau formation) and thereby facilitate the removal of erythroid cells from solution. Antibodies against cell surface antigens can facilitate the removal of blood cells from solution via homotypic agglutination (i.e., agglutination of cells of the same cell type) and/or heterotypic agglutination (i.e., agglutination of cells of different cell types).

[0018] Cell separation compositions can contain antibodies against blood cell surface antigens including, for example, glycophorin A, CD15, CD9, CD2, CD3, CD4, CD8, CD72, CD16, CD41a, HLA Class I, HLA-DR, CD29, CD11a, CD11b, CD11c, CD19, CD20, CD23, CD39, CD40, CD43, CD44, CDw49d, CD53, CD54, CD62L, CD63, CD66, CD67, CD81, CD82, CD99, CD100, Leu-13, TPA-1, surface Ig, and combinations thereof. Thus, cell separation compositions can be formulated to selectively agglutinate particular types of blood cells.

[0019] In some embodiments, a cell separation composition includes antibodies against glycophorin A. Anti-glycophorin A antibodies can facilitate the removal of red cells from solution by at least two mechanisms. First, anti-glycophorin A antibodies can cause homotypic agglutination of erythrocytes since glycophorin A is the major surface glycoprotein on erythrocytes. In addition, anti-glycophorin A antibodies also can stabilize dextran-mediated rouleau formation. Exemplary monoclonal anti-glycophorin A antibodies include, without limitation, 107FMN (Murine IgG1 Isotype), YTH89.1 (Rat IgG2b Isotype), and E4 (Murine IgM Isotype). See e.g., M. Vanderlaan et al., Molecular Immunology 20:1353 (1983); Telen M. J. and Bolk, T. A., Transfusion 27: 309 (1987); and Outram S. et al., Leukocyte Research. 12:651 (1988).

[0020] In some embodiments, a cell separation composition includes antibodies against CD15. Anti-CD15 antibodies can cause homotypic agglutination of granulocytes by crosslinking CD15 molecules that are present on the surface of granulocytes. Anti CD15 antibodies also can cause homotypic and heterotypic agglutination of granulocytes with monocytes, NK-cells and B-cells by stimulating expression of adhesion molecules (e.g., L-selectin and beta-2 integrin) on the surface of granulocytes that interact with adhesion molecules on monocytes, NK-cells and B-cells. Heterotypic agglutination of these cell types can facilitate the removal of these cells from solution along with red cell components. Exemplary monoclonal anti-CD15 antibodies include, without limitation, AHN 1.1 (Murine IgM Isotype), FMC-10 (Murine IgM Isotype), BU-28 (Murine IgM Isotype), MEM-157 (Murine IgM Isotype), MEM-158 (Murine IgM Isotype), MEM-167 (Murine IgM Isotype). See e.g., Leukocyte typing IV (1989); Leukocyte typing II (1984); Leukocyte typing VI (1995); Solter D. et al., Proceedings of National Academy of Sciences USA 75:5565 (1978); Kannagi R. et al., Journal of Biological Chemistry 257:14865 (1982); Magnani, J. L. et al., Archives of Biochemistry and Biophysics 233:501 (1984); Eggens I. et al., Journal of Biological Chemistry 264:9476 (1989).

[0021] In some embodiments, a cell separation composition includes antibodies against CD9. Anti-CD9 antibodies can cause homotypic agglutination of platelets. Anti-CD9 antibodies also can cause heterotypic agglutination of granulocytes and monocytes via platelets that have adhered to the surface of granulocytes and monocytes. CD9 antibodies can promote the expression of platelet 1-selectin, which facilitates the binding of platelets to leukocyte cell surfaces. Thus, anti-CD9 antibodies can promote multiple cell-cell linkages and thereby facilitate agglutination and removal from solution. Exemplary monoclonal anti-CD9 antibodies include, without limitation, MEM-61 (Murine IgGI Isotype), MEM-62 (Murine IgG1 Isotype), MEM-192 (Murine IgM Isotype), FMC-8 (Murine IgG2a Isotype), SN4 (Murine IgG1 Isotype), BU-16 (Murine IgG2a Isotype). See e.g., Leukocyte typing VI (1995); Leukocyte typing II (1984); Von dem Bourne A. E. G. Kr. and Moderman P. N. (1989) In Leukocyte typing IV (ed. W. Knapp, et al), pp. 989-92. Oxford University Press, Oxford; Jennings, L. K., et al. In Leukocyte typing V, ed. S. F. Schlossmann et al., pp. 1249-51. Oxford University Press, Oxford (1995); Lanza F. et al., Journal of Biological Chemistry 266:10638 (1991); Wright et al., Immunology Today 15:588 (1994); Rubinstein E. et al., Seminars in Thrombosis and Hemostasis 21:10 (1995).

[0022] In some embodiments, a cell separation composition contains antibodies against CD41, which can selectively agglutinate platelets. In some embodiments, a cell separation composition contains antibodies against CD3, which can selectively agglutinate T-cells. In some embodiments, a cell separation composition contains antibodies against CD2, which can selectively agglutinate T-cells and NK cells. In some embodiments, a cell separation composition contains antibodies against CD72, which can selectively agglutinate B-cells. In some embodiments, a cell separation composition contains antibodies against CD16, which can selectively agglutinate NK cells and neutrophilic granulocytes.

[0023] As mentioned above, cell separation compositions can be formulated to selectively agglutinate particular blood cells. As an example, a cell separation composition containing antibodies against glycophorin A, CD15, and CD9 can facilitate the agglutination of erythrocytes, granulocytes, NK cells, B cells, and platelets. T cells, NK cells and rare precursor cells then can be recovered from solution. If the formulation also contained an antibody against CD3, T cells also could be agglutinated, and NK cells and rare precursors could be recovered from solution.

[0024] Cell separation compositions can contain antibodies against surface antigens of other types of cells (e.g., cell surface proteins of tumor cells). Those of skill in the art can use routine methods to prepare antibodies against cell surface antigens of blood, and other, cells from humans and other mammals, including, for example, non-human primates, rodents (e.g., mice, rats, hamsters, rabbits and guinea pigs), swine, bovines, and equines.

[0025] Typically, antibodies used in the composition are monoclonal antibodies, which are homogeneous populations of antibodies to a particular epitope contained within an antigen. Suitable monoclonal antibodies are commercially available, or can be prepared using standard hybridoma technology. In particular, monoclonal antibodies can be obtained by techniques that provide for the production of antibody molecules by continuous cell lines in culture, including the technique described by Kohler, G. et al., Nature, 1975, 256:495, the human B-cell hybridoma technique (Kosbor et al., Immunology Today 4:72 (1983); Cole et al., Proc. Natl. Acad. Sci. USA 80:2026 (1983)), and the EBV-hybridoma technique (Cole et al., “Monoclonal Antibodies and Cancer Therapy,” Alan R. Liss, Inc., pp. 77-96 (1983)).

[0026] Antibodies can be of any immunoglobulin class including IgG, IgM, IgE, IgA, IgD, and any subclass thereof. Antibodies of the IgG and IgM isotypes are particularly useful in cell separation compositions of the invention. Pentameric IgM antibodies contain more antigen binding sites than IgG antibodies and can, in some cases (e.g., anti-glycophorin A and anti-CD15), be particularly useful for cell separation reagents. In other cases (e.g., anti-CD9 antibodies), antibodies of the IgG isotype are particularly useful for stimulating homotypic and/or heterotypic agglutination.

[0027] Antibodies against cell surface antigens can be provided in liquid phase (i.e., soluble). Liquid phase antibodies typically are provided in a cell separation composition at a concentration between about 0.1 and about 15 mg/l (e.g., between 0.25 to 10, 0.25 to 1, 0.5 to 2, 1 to 2, 4 to 8, 5 to 10 mg/l).

[0028] Antibodies against cell surface antigens also can be provided in association with a solid phase (i.e., substrate-bound). Antibodies against different cell surface antigens can be covalently linked to a solid phase to promote crosslinking of cell surface molecules and activation of cell surface adhesion molecules. The use of substrate-bound antibodies can facilitate cell separation (e.g., by virtue of the mass that the particles contribute to agglutinated cells, or by virtue of properties useful for purification).

[0029] In some embodiments, the solid phase with which an substrate-bound antibody is associated is particulate. In some embodiments, an antibody is bound to a latex microparticle such as a paramagnetic bead (e.g., via biotin-avidin linkage, covalent linkage to COO groups on polystyrene beads, or covalent linkage to NH₂ groups on modified beads). In some embodiments, an antibody is bound to an acid-etched glass particle (e.g., via biotin-avidin linkage). In some embodiments, an antibody is bound to an aggregated polypeptide such as aggregated bovine serum albumin (e.g., via biotin-avidin linkage, or covalent linkage to polypeptide COO groups or NH₂ groups). In some embodiments, an antibody is covalently linked to a polysaccharide such as high molecular weight (e.g., >1,000,000 M_(r)) dextran sulfate. In some embodiments, biotinylated antibodies are linked to avidin particles, creating tetrameric complexes having four antibody molecules per avidin molecule. In some embodiments, antibodies are bound to biotinylated agarose gel particles (One Cell Systems, Cambridge, MA, U.S.A.) via biotin-avidin-biotinylated antibody linkages. Such particles typically are about 300-500 microns in size, and can be created in a sonicating water bath or in a rapidly mixed water bath.

[0030] Cell-substrate particles (i.e., particles including cells and substrate-bound antibodies) can sediment from solution as an agglutinate. Cell-substrate particles also can be removed from solution by, for example, an applied magnetic field, as when the particle is a paramagnetic bead. Substrate-bound antibodies typically are provided in a cell separation composition at a concentration between about 0.1 and about 50.0×10⁹ particles/l (e.g., between 0.25 to 10.0×10⁹, 1 to 20.0×10⁹, 2 to 10.0×10⁹, 0.5 to 2×10⁹, 2 to 5×10⁹, 5 to 10×10⁹, and 10 to 30×10⁹ particles/l), where particles refers to solid phase particles having antibodies bound thereto.

[0031] Cell separation compositions also can contain divalent cations (e.g., Ca⁺² and Mg⁺²). Divalent cations can be provided, for example, by a balanced salt solution (e.g., Hank's balanced salt solution). Ca⁺² ions reportedly are important for selectin-mediated and integrin-mediated cell-cell adherence.

[0032] Cell separation compositions of the invention also can contain an anticoagulant such as heparin. Heparin can prevent clotting and non-specific cell loss associated with clotting in a high calcium environment. Heparin also promotes platelet clumping. Clumped platelets can adhere to granulocytes and monocytes and thereby enhance heterotypic agglutination more so than single platelets. Heparin can be supplied as a heparin salt (e.g., sodium heparin, lithium heparin, or potassium heparin).

[0033] Cell Separation Methods

[0034] The disclosed compositions can be used, for example, to efficiently prepare cells for tissue culture, immunophenotypic characterization, other diagnostic testing, further purification, and therapeutic administration. Without being bound by a particular mechanism, compositions of the invention can selectively agglutinate cells via interaction with cell surface antigens and/or by stimulating cell-cell adherence (e.g., via increased expression of cell surface adhesion factors). Agglutinated cells partition away from unagglutinated cells, which remain in solution.

[0035] After agglutination, unagglutinated cells can be recovered from the solution phase. Cells also can be recovered from the agglutinate. Agglutinated cells can be dissociated by, for example, transferring the cells into buffers that contain divalent cation chelators such as EDTA or EGTA. Cells recovered from the agglutinate can be further separated by using antibodies against cell surface antigens. Cells can be recovered from a gel microparticle-antibody-cell agglutinate by heating the agglutinate to a temperature just above the melting point.

[0036] The disclosed compositions can be used to separate cells from a variety of samples, including peripheral blood (e.g., obtained by venipuncture), umbilical cord blood (e.g., obtained post-gravida), and bone marrow (e.g., from aspirate). Blood cell-containing samples can be contacted with a cell separation composition to cause agglutination of particular types of cells. For example, erythrocytes and differentiated myeloid blood constituents can be selectively agglutinated using cell separation compositions containing antibodies to surface antigens of these cells. The disclosed compositions and methods can be used to isolate and enrich for a variety of cell types, including, for example, T lymphocytes, T helper cells, T suppressor cells, B cells, hematopoietic stem cells, circulating embryonic stem cells, circulating fetal cells in maternal circulation, and circulating metastatic tumor cells. The disclosed compositions can used to agglutinate cells of any mammal, including humans, non-human primates, rodents, swine, bovines and equines.

[0037] The disclosed compositions and methods can be used in the context of allogenic and autologous transplantation. In the context of autologous transplantation, the disclosed compositions and methods can be used, for example, to remove undesired cells such as metastatic cancer cells from a patient's blood or bone marrow. Desirable cells (e.g., hematopoietic stem cells) then can be returned back to a patient without, or substantially free of, life-threatening tumor cells.

[0038] Cell separation compositions containing antibodies against cell surface proteins of tumor cells can be used to purge tumor cells from a patient's blood or bone marrow. Such compositions also can be used for diagnostic procedures to, for example, obtain and detect tumor cells in an agglutinate, where they are concentrated and are therefore more easily detectable than in circulating blood or in bone marrow. A cell separation composition containing antibodies against the receptor for epithelial growth factor can be used to agglutinate tumor cells derived from epithelial tumors (e.g., head and neck tumors). A cell separation composition containing antibodies against estrogen receptors can be used to agglutinate tumor cells derived from breast and ovarian tumors. A cell separation composition containing antibodies against surface immunoglobulins can be used to agglutinate tumor cells associated with chronic lymphocytic leukemia, plasmacytoma, and multiple myeloma. Breast carcinoma cells express CD15 on their cell surface, and can be purged from bone marrow using cell separations that contain antibodies against CD15. Other formulas can be made on the basis of cell type and cell surface proteins to obtain or deplete metastatic tumor cells derived from other carcinomas (e.g., erythroleukemia, endothelial carcinoma, and gastrointestinal carcinoma) from a patient's blood or bone marrow.

[0039] Cell Separation Kits

[0040] A cell separation composition can be combined with packaging material and sold as a kit. The components of a cell separation composition can be packaged individually or in combination with one another. In some embodiments, the packaging material includes a blood collection vessel (e.g., blood bag, vacuum tube). The packaging material included in a kit typically contains instructions or a label describing how the cell separation composition can be used to agglutinate particular types of cells. Components and methods for producing such kits are well known.

[0041] The invention is further described in the following examples, which do not limit the scope of the invention described in the claims.

EXAMPLES

[0042] Example 1: Separating blood cells.

[0043] This example describes the general method by which cells were separated using the cell separation reagents described below. An equal volume of a cell separation reagent (i.e., 25 ml) was combined with an equal volume of an EDTA anti-coagulated heparinized peripheral blood sample (i.e., 25 ml) in a 50 ml conical tube. Samples containing white blood cell counts greater than 20×10⁶ cells/ml were combined one part blood with two parts cell separation reagent. Tubes were gently mixed on a rocker platform for 30 to 45 minutes at room temperature. Tubes were stood upright in a rack for 30 to 50 minutes to permit agglutinated cells to partition away from unagglutinated cells, which remained in solution. Without disturbing the agglutinate, a pipette was used to recover unagglutinated cells from the supernatant. Recovered cells were washed in 25 ml PBS and centrifuged at 500× g for 7 minutes. The cell pellet was resuspended in 4 ml PBS.

[0044] Cells also were recovered from the agglutinate using a hypotonic lysing solution containing ethylenediaminetetraacetic acid (EDTA) and ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA). Agglutinated cells were treated with 25 ml VitaLyse™ (BioErgonomics, St. Paul, Minn.) and vortexed. After 10 minutes, cells either were exposed to an applied magnetic field to recover cells associated with antibodies bound to paramagnetic beads, or were centrifuged at 500× g for 7 minutes and the supernatant was removed. In either case, cells were resuspended in 4 ml PBS.

[0045] Recoveries of erythrocytes, leukocytes, lymphocytes, monocytes, granulocytes, T cells, B cells, and NK cells were determined by flow cytometry and immunophenotyping. Prior to flow cytometry, leukocyte recovery (i.e., white blood cell count) was determined using a Coulter Onyx Hematology Analyzer, and samples were adjusted with PBS to a cell count of 1×10⁷ cells/ml. 100 ul aliquots of volume-adjusted sample were stained at room temperature in the dark for 15 to 30 minutes with either FITC labeled anti-CD3 antibodies (reactive to T cells), PE labeled anti-CD19 antibodies (reactive to B cells), or PE labeled anti-CD16 antibodies (reactive to NK cells). 2 ml of PBS was added to each sample, and the sample was then vortexed and centrifuged to pellet cells. Supernatants were discarded, and cell pellets were vortexed and resuspended in 0.5 ml PBS. Stained and unstained cells were analyzed by flow cytometry using a Coulter XL flow cytometer. Erythrocytes, leukocytes, lymphocytes, monocytes, granulocytes and platelets were identified on the basis of diagnostic forward and side light scatter properties. B cells, T cells, and NK cells were identified on the basis of light scattering and staining by labeled antibodies.

[0046] Example 2: Erythrocyte agglutination.

[0047] The reagent described in Table 1 was used to separate cells according to the method described in Example 1. TABLE 1 Dextran (average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Sodium Heparin (10,000 units/ml)  1 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Anti-human glycophorin A (murine IgM monoclonal antibody 1.0 mg/l clone E4)

[0048] Results of a separation are shown in Table 2. Erythrocytes were depleted 99.7% from the supernatant. Lymphocytes (T cells, B cells, and NK cells) were enriched in the supernatant relative to the monocytes and granulocytes. TABLE 2 Before separation After separation Erythrocytes per ml 4.41 × 10⁹ 0.015 × 10⁹ Leukocytes per ml  5.9 × 10⁶  5.3 × 10⁶ Lymphocytes (%) 28.7 41.9 Monocytes (%) 8.69 4.78 Granulocytes (%) 62.5 52.6 T Cells (CD3+) 19.7 31.8 B Cells (CD19+) 4.46 5.42 NK Cells (CD16+) 3.15 5.9

[0049] Example 3: Erythrocyte and CD2+ cell agglutination.

[0050] The reagent described in Table 3 was used to separate cells according to the method described in Example 1. TABLE 3 Dextran (average molecular weight 413,000)   20 g/l Dulbecco's phosphate buffered saline (10X)  100 ml/l Sodium Heparin (10,000 units/ml)   1 ml/l Hank's balanced salt solution (pH 7.2-7.4)   50 ml/l Anti-human glycophorin A (murine IgM  1.0 mg/l monoclonal antibody, clone E4 Anti-human CD2 paramagnetic agglutination particles 14.02 × 10⁹ (avidin-coated 4.3 micron diameter paramagnetic particles/l polystyrene particles labeled with saturating doses of biotin-labeled mouse anti-human CD2, clone d118.10.1)

[0051] Results of a separation are shown in Table 4. In the supernatant, erythrocytes were depleted 99.7%, T cells were depleted 95.1%, and NK cells were depleted 69.1%. B cells were enriched in the supernatant relative to other cells. TABLE 4 Before separation After separation Erythrocytes per ml 4.41 × 10⁹ 0.014 × 10⁹ Leukocytes per ml  5.9 × 10⁶  2.63 × 10⁶ Lymphocytes (%) 28.7 16.0 Monocytes (%) 8.69 6.04 Granulocytes (%) 62.5 75.6 T Cells (CD3+) 19.7 3.3 B Cells (CD19+) 4.46 9.63 NK Cells (CD16+) 3.15 4.32

[0052] Example 4: Erythrocyte and CD72+ cell agglutination.

[0053] The reagent described in Table 5 was used to separate cells according to the method described in Example 1. TABLE 5 Dextran (average molecular weight 413,000)   20 g/l Dulbecco's phosphate buffered saline (10X)  100 ml/l Sodium Heparin (10,000 units/ml)   1 ml/l Hank's balanced salt solution (pH 7.2-7.4)   50 ml/l Anti-human glycophorin A (murine IgM  1.0 mg/l monoclonal antibody, clone E4) Anti-human CD72 paramagnetic agglutination 2.63 × 10⁶ particles (avidin-coated 4.3 micron diameter particles/ml paramagnetic polystyrene particles labeled with saturating doses of biotin-labeled mouse anti-human CD72, clone BU40)

[0054] Results of a separation are shown in Table 6. In the supernatant, erythrocytes were depleted 99.5%, and B cells were depleted 81.6%. TABLE 6 Before separation After separation Erythrocytes per ml 4.41 × 10⁹ 0.021 × 10⁹ Leukocytes per ml  5.9 × 10⁶  3.2 × 10⁶ Lymphocytes (%) 28.7 47.0 Monocytes (%) 8.69 4.78 Granulocytes (%) 62.5 47.7 T Cells (CD3+) 19.7 41.3 B Cells (CD19+) 4.46 2.75 NKCells(CD16+) 3.15 4.77

[0055] Example 5: Erythrocyte, CD15+ cell, and CD9+ cell agglutination.

[0056] The reagent described in Table 7 was used to separate cells according to the method described in Example 1. TABLE 7 Dextran (average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Sodium Heparin (10,000 units/ml)  1 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Anti-human glycophorin A (murine IgM 0.1-15 mg/l monoclonal antibody, clone E4) (preferably about 1.0 mg/l) Anti-CD15 (murine IgM monoclonal antibody, 0.1-15 mg/l clone MEM-158) (preferably about 1.0 mg/l) Anti-CD9 (murine IgG monoclonal antibody, 0.1-15 mg/l clone MEM-61) (preferably about 1.0 mg/l)

[0057] Results of a separation are shown in Table 8. In the supernatant, erythrocytes were depleted 99.9%, monocytes and granulocytes were depleted 99.8%, B cells were depleted 74%, and NK cells were depleted 64.9%. In addition, platelets, present in the supernatant at 226×10⁶/ml before separation, were depleted to 1.4×10⁶/ml for 99.4% depletion. TABLE 8 Before separation After separation Erythrocytes per ml 4.41 × 10⁹ 0.006 × 10⁹ Leukocytes per ml  5.9 × 10⁶  1.53 × 10⁶ Lymphocytes (%) 28.7 99.0 Monocytes (%) 8.69 0.12 Granulocytes (%) 62.5 .083 T Cells (CD3+) 19.7 83.2 B Cells (CD19+) 4.46 8.10 NK Cells (CD16+) 3.15 8.43

[0058] Example 6: Erythrocyte, CD15+ cell, CD9+ cell, and CD2+ cell agglutination.

[0059] The reagent described in Table 9 was used to separate cells according to the method described in Example 1. TABLE 9 Dextran (average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Sodium Heparin (10,000 units/mi)  1 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Anti-human glycophorin A (murine IgM  1 mg/l monoclonal antibody, clone E4) Anti-CD 15 (murine IgM monoclonal antibody,  1 mg/l clone MEM-158) Anti-CD9 (murine IgG monocional antibody, clone  1 mg/l MEM-61) Anti-human CD2 paramagnetic agglutination 14.02 × 10⁹ particles (avidin-coated 4.3 micron diameter particles/l paramagnetic polystyrene particles labeled with saturating doses of biotin-labeled mouse anti- human CD2, clone d118.10.1)

[0060] Results of a separation are shown in Table 10. In the supernatant, erythrocytes were depleted 99.9%, monocytes and granulocytes were depleted 99.9%, B cells were depleted 16.8%, NK cells were depleted 29%, and T cells were depleted 91.5%. In addition, platelets, present in the supernatant at 226×10⁶/ml before separation, were depleted to 0.3×10⁶/ml for 99.9% depletion. TABLE 10 Before separation After separation Erythrocytes per ml 4.41 × 10⁹ 0.005 × 10⁹ Leukocytes per ml  5.9 × 10⁶  1.26 × 10⁶ Lymphocytes (%) 28.7 99.8 Monocytes (%) 8.69 0.06 Granulocytes (%) 62.5 0.09 T Cells (CD3+) 19.7 6.78 B Cells (CD19+) 4.46 69.5 NK Cells (CDl6+) 3.15 20.7

[0061] Example 7: Erythrocyte, CD15+ cell, CD9+ cell, and CD72+ cell agglutination.

[0062] The reagent described in Table 11 was used to separate cells according to the method described in Example 1. TABLE 11 Dextran (average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Sodium Heparin (10,000 units/ml)  1 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Anti-human glycophorin A (murine IgM  1 mg/l monoclonal antibody, clone E4) Anti-CD15 (murine IgM monoclonal antibody,  1 mg/l clone MEM-158) Anti-CD9 (murine IgG monoclonal antibody,  1 mg/l clone MEM-61) Anti-human CD72 paramagnetic agglutination 2.63 × 10^(9 particles/l) particles (avidin-coated 4.3 micron diameter paramagnetic polystyrene particles labeled with saturating doses of biotin-labeled mouse anti- human CD72, clone BU40)

[0063] Results of a separation are shown in Table 12. In the supernatant, erythrocytes were depleted 99.9%, monocytes were depleted beyond detection, granulocytes were depleted 99.97%, B cells were depleted 97.2%, NK cells were depleted 54.9%. In addition, platelets, present in the supernatant at 226×10⁶/ml before separation, were depleted to 0.1×10⁶/ml for 99.96% depletion. TABLE 12 Before separation After separation Erythrocytes per ml 4.41 × 10⁹ 0.006 × 10⁹ Leukocytes per ml  5.9 × 10⁶  2.3 × 10⁶ Lymphocytes (%) 28.7 99.9 Monocytes (%) 8.69 0 Granulocytes (%) 62.5 0.1 T Cells (CD3+) 19.7 92.4 B Cells (CD19+) 4.46 0.59 NK Cells (CD16+) 3.15 7.02

[0064] Example 8: Erythrocyte, CD15+ cell, CD9+ cell, CD9+ cell, and CD16+ cell agglutination.

[0065] The reagent described in Table 13 was used to separate cells according to the method described in Example 1. T cells and CD3+ cells were recovered from the supernatant. B cells and granulocytes are recovered from the agglutinate. TABLE 13 Dextran (average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Sodium Heparin (10,000 units/ml)  1 ml/l Anti-human glycophorin A (murine IgM 0.1-15 mg/l monoclonal antibody, clone E4) (preferably about 1.0 mg/l) Anti-human CD15 (murine IgM 0.1-15 mg/l monoclonal antibody, clone MEM-158) (preferably about 1.0 mg/l) Anti-human CD9 (murine IgM monoclonal 0.1-15 mg/l antibody, clone MEM-61) (preferably about 1.0 mg/l) Anti-CD 19 paramagnetic agglutination 0.1-30.0 × 10⁹ particles/l particles (avidin-coated 4.3 micron diameter (preferably about 19.8 × paramagnetic polystyrene particles labeled 10⁹ particles/l) with saturating doses of biotin-labeled mouse anti-human CD19, clone HIB19) Anti-CD16 paramagnetic agglutination 5.5 × 10¹¹ particles/l particles (avidin-coated 4.3 micron diameter paramagnetic polystyrene particles labeled with saturating doses of biotin-labeled mouse anti-human CD16, clone 3G8)

[0066] Example 9: Erythrocyte, CD15+ cell, CD9+ cell, CD9+ cell, CD16+ cell, and CD4+ cell agglutination.

[0067] The reagent described in Table 14 was used to separate cells according to the method described in Example 1. CD8+ cells were recovered from the supernatant. TABLE 14 Dextran (average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Sodium Heparin (10,000 units/ml)  1 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Anti-human glycophorin A (murine IgM 0.1-15 mg/l monoclonal antibody, clone E4) (preferably about 1.0 mg/l Anti-human CDl5 (murine IgM monoclonal 0.1-15 mg/l antibody, clone MEM-158) (preferably about 1.0 mg/l Anti-human CD9 (murine IgM monoclonal 0.1-15 mg/l antibody, clone MEM-61) (preferably about 1.0 mg/l) Anti-CD19 paramagnetic agglutination particles 0.1-30.0 × 10⁹ (avidin-coated 4.3 micron diameter particles/l paramagnetic polystyrene particles labeled (preferably about with saturating doses of biotin-labeled mouse 19.8 × 10⁹ anti-human CD 19, clone HIB19) particles/l) Anti-CD16 paramagnetic agglutination particles 5.5 × 10¹¹ particles/l (avidin-coated 4.3 micron diameter paramagnetic polystyrene particles labeled with saturating doses of biotin-labeled mouse anti-human CD16, clone 3G8) Anti-CD4 paramagnetic agglutination particles 1.2 × 10¹⁰ particles/l (avidin-coated 4.3 micron diameter paramagnetic polystyrene particles labeled with saturating doses of biotin-labeled mouse anti-human CD4, clone RFT4-α or clone QS4120)

[0068] Example 10: Erythrocyte, CD15+ cell, CD9+ cell, CD19+ cell, CD16+ cell, and CD8+ cell agglutination.

[0069] The reagent described in Table 15 is used to separate cells according to the method described in Example 1. CD4+ cells are recovered from the supernatant. TABLE 15 Dextran (Average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Sodium Heparin (10,000 units/ml)  1 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Anti-human glycophorin A (murine IgM 0.1-15 mg/l monoclonal Antibody) clone E4 (preferably about 1.0 mg/l) Anti-human CD15 (murine IgM monoclonal 0.1-15 mg/l Antibody) (clone MEM-158) (preferably about 1.0 mg/l) Anti-human CD9 (murine IgM monoclonal 0.1-15 mg/l antibody) (clone MEM-61) (preferably about 1.0 mg/l) Anti-CD19 agglutination particles (avidin-coated 0.1-30.0 × 10⁹ 4.3 micron diameter paramagnetic polystyrene particles/l particles labeled with saturating doses of (preferably about biotin-labeled mouse anti-human CD19 (clone HIB19) 19.8 × 10⁹ particles/l) Anti-CD16 agglutination particle (avidin-coated 5.5 × 10¹¹ 4.3 micron diameter paramagnetic polystyrene particles/l particles labeled with saturating doses of biotin-labeled mouse anti-human CD16 (clone 3G8) Anti-CD8 agglutination particle (avidin-coated 7.92 × 10⁹ 4.3 micron diameter paramagnetic polystyrene particles/l particles labeied with saturating doses of biotin-labeled mouse anti-human CD8 (clone HIT8a)

[0070] Example 11: Erythrocyte, CD15+ cell, CD9+ cell, CD19+ cell, and CD2+ cell agglutination.

[0071] The reagent described in Table 16 was used to separate cells according to the method described in Example 1. CD34+ cells were recovered from the supernatant at >50% purity and >80% yield. TABLE 16 Dextran (average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Sodium Heparin (10,000 units/ml)  1 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Anti-human glycophorin A (murine IgM 0.1-15 mg/l monoclonal antibody, clone E4) (preferably about 1.0 mg/l) Anti-human CD15 (murine IgM 0.1-15 mg/l monoclonal antibody, clone MEM-158) (preferably about 1.0 mg/l) Anti-human CD9 (murine IgM 0.1-15 mg/l monoclonal antibody, clone MEM-61) (preferably about 1.0 mg/l) Anti- CD19 agglutination particles (avidin-coated 0.1-30.0 × 10⁹ 4.3 micron diameter paramagnetic polystyrene particles/l particles labeled with saturating doses of biotin-labeled (preferably about mouse anti-human CD19, clone HIB19) 19.8 × 10⁹ particles/l) Anti-CD2 agglutination particles (avidin-coated 0.1-30.0 × 10⁹ 4.3 micron diameter paramagnetic polystyrene particies/l particles labeled with saturating doses of biotin-labeled (preferably about mouse anti-human CD2, clone d118.10.1) 3.0 × 10¹⁰ particles/l)

[0072] Example 12: Erythrocyte, CD15+ cell, CD9+ cell, CD2+ cell, and CD16+ cell agglutination.

[0073] The reagent described in Table 17 was used to separate cells according to the method described in Example 1. B cells were recovered from the supernatant. TABLE 17 Dextran (average molecular weight 413,000)  20 g/l Dulbecco's phosphate buffered saline (10X) 100 ml/l Sodium Heparin (10,000 units/ml) °1 ml/l Hank's balanced salt solution (pH 7.2-7.4)  50 ml/l Anti-human glycophorin A (murine IgM 0.1-15 mg/l monoclonal antibody, clone E4) (preferably about 1.0 mg/l) Anti-human CD15 (murine IgM monoclonal 0.1-15 mg/l antibody, clone MEM-158) (preferably about 1.0 mg/l) Anti-human CD9 (murine IgM monoclonal 0.1-15 mg/l antibody, clone (preferably about 1.0 mg/l) Anti-CD2 agglutination particles (avidin-coated 0.1-30.0 × 10⁹ 4.3 micron diameter paramagnetic polystyrene particles/l particles labeled with saturating doses of biotin- (preferably about 3.0 × labeled mouse anti-human CD2, clone d118.10.1) 10¹⁰ particles/l) Anti-CD 16 agglutination particles (avidin-coated 5.5 × 10¹¹ 4.3 micron diameter paramagnetic polystyrene particles/l particles labeled with saturating doses of biotin- labeled mouse anti-human CD16, clone 3G8)

Other Embodiments

[0074] While the invention has been described in conjunction with the foregoing detailed description and examples, the foregoing description and examples are intended to illustrate and not to limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the claims. 

What is claimed is:
 1. A composition comprising: a) dextran; b) anti-glycophorin A antibody; c) anti-CD15 antibody; and d) anti-CD9 antibody.
 2. The composition of claim 1, further comprising anti-CD3 antibody.
 3. The composition of claim 1, further comprising anti-CD72 antibody.
 4. The composition of claim 1, further comprising anti-CD16 antibody.
 5. The composition of claim 1, further comprising anti-CD4 antibody.
 6. The composition of claim 1, further comprising anti-CD8 antibody.
 7. The composition of claim 1, further comprising anti-CD2 antibody.
 8. The composition of claim 1, further comprising heparin.
 9. The composition of claim 1, further comprising divalent cations.
 10. The composition of claim 3, wherein said divalent cations are Ca+2.
 11. The composition of claim 3, wherein said divalent cations are Mg+2.
 12. The composition of claim 1, further comprising phosphate buffered saline.
 13. The composition of claim 1, wherein the pH of said composition is between 6.8 to 7.8.
 14. The composition of claim 1, wherein the pH of said composition is between 7.2 to 7.4.
 15. The composition of claim 1, wherein said anti-glycophorin A antibody is monoclonal.
 16. The composition of claim 1, wherein said anti-glycophorin A antibody is an IgM antibody.
 17. The composition of claim 1, wherein said anti-glycophorin A antibody is an IgG antibody.
 18. The composition of claim 1, wherein said anti-glycophorin A antibody is an anti-human glycophorin A antibody.
 19. The composition of claim 1, wherein the concentration of said anti-glycophorin A antibody is about 0.1 mg/l to about 15 mg/l.
 20. The composition of claim 1, wherein said anti-CD15 antibody is a monoclonal antibody.
 21. The composition of claim 1, wherein said anti-CD15 antibody is an IgM antibody.
 22. The composition of claim 1, wherein said anti-CD15 antibody is an IgG antibody.
 23. The composition of claim 1, wherein said anti-CD15 antibody is an anti-human CD15 antibody.
 24. The composition of claim 1, wherein the concentration of said anti-CD15 antibody is about 0.1 mg/l to about 15 mg/l.
 25. The composition of claim 1, wherein said anti-CD9 antibody is a monoclonal antibody.
 26. The composition of claim 1, wherein said anti-CD9 antibody is an IgM antibody.
 27. The composition of claim 1, wherein said anti-CD9 antibody is an IgG antibody.
 28. The composition of claim 1, wherein said anti-CD9 antibody is an anti-human CD9 antibody.
 29. The composition of claim 1, wherein the concentration of said anti-CD9 antibody is at about 0.1 mg/l to about 15 mg/l.
 30. A composition comprising: a) dextran; b) anti-glycophorin A antibody; c) anti-CD15 antibody; d) anti-CD9 antibody; e) heparin; and f) divalent cations.
 31. A kit comprising a blood collection vessel and a cell separation composition, said cell separation composition comprising: a) dextran; b) anti-glycophorin A antibody; c) anti-CD15 antibody; and d) anti-CD9 antibody.
 32. The kit of claim 31, wherein said blood collection vessel is a blood bag.
 33. The kit of claim 31 wherein said blood collection vessel is a vacuum tube.
 34. A method for separating cells, said method comprising: a) contacting a blood cell-containing sample with a composition, said composition comprising: i) dextran; ii) anti-glycophorin A antibody; iii) anti-CD15 antibody; and iv) anti-CD9 antibody; and b) allowing said sample to partition into an agglutinate and a supernatant phase; and c) recovering said cells.
 35. The method of claim 34, wherein said sample is derived from a human.
 36. The method of claim 35, wherein said sample is a peripheral blood sample.
 37. The method of claim 35, wherein said sample is an umbilical cord sample.
 38. The method of claim 35, wherein said sample is a bone marrow sample.
 39. The method of claim 35, wherein said cells are metastatic tumor cells.
 40. The method of claim 35, wherein said cells are recovered from said supematant phase.
 41. The method of claim 40, wherein said cells are stem cells.
 42. A composition comprising: a) dextran; b) anti-glycophorin A antibody; and c) a substrate-bound antibody against a cell surface antigen.
 43. The composition of claim 42, wherein said substrate-bound antibody is bound to a latex microparticle.
 44. The composition of claim 42, wherein said substrate-bound antibody is bound to an acid-etched glass particle.
 45. The composition of claim 42, wherein said substrate-bound antibody is bound to an aggregated polypeptide.
 46. The composition of claim 42, wherein said substrate-bound antibody is bound to a polysaccharide.
 47. The composition of claim 42, wherein said substrate-bound antibody is bound to an avidin particle.
 48. The composition of claim 42, wherein said substrate-bound antibody is bound to a biotinylated agarose gel particle.
 49. The composition of claim 42, wherein said antibody is anti-CD15.
 50. The composition of claim 42, wherein said antibody is anti-CD9.
 51. The composition of claim 42, wherein said antibody is anti-CD3.
 52. The composition of claim 42, wherein said antibody is anti-CD72.
 53. The composition of claim 42, wherein said antibody is anti-CD16.
 54. The composition of claim 42, wherein said antibody is anti-CD4.
 55. The composition of claim 42, wherein said antibody is anti-CD8.
 56. The composition of claim 42, wherein said antibody is anti-CD2.
 57. The composition of claim 42, wherein said antibody is anti-CD3.
 58. The composition of claim 42, further comprising heparin.
 59. The composition of claim 42, further comprising divalent cations.
 60. The composition of claim 59, wherein said divalent cations are Ca+2.
 61. The composition of claim 59, wherein said divalent cations are Mg+2.
 62. The composition of claim 42, further comprising phosphate buffered saline.
 63. The composition of claim 42, wherein the pH of said composition is between 6.8 to 7.8.
 64. The composition of claim 42, wherein the pH of said composition is between 7.2 to 7.4.
 65. The composition of claim 42, wherein said anti-glycophorin A antibody is monoclonal.
 66. The composition of claim 42, wherein said anti-glycophorin A antibody is an IgM antibody.
 67. The composition of claim 42, wherein said anti-glycophorin A antibody is an IgG antibody.
 68. The composition of claim 42, wherein said anti-glycophorin A antibody is an anti-human glycophorin A antibody.
 69. The composition of claim 42, wherein the concentration of said anti-glycophorin A antibody is about 0.1 mg/l to about 15 mg/l.
 70. The composition of claim 42, wherein said anti-glycophorin A antibody is substrate-bound.
 71. The composition of claim 49, wherein said anti-CD15 antibody is a monoclonal antibody.
 72. The composition of claim 49, wherein said anti-CD15 antibody is an IgM antibody.
 73. The composition of claim 49, wherein said anti-CD15 antibody is an IgG antibody.
 74. The composition of claim 49, wherein said anti-CD15 antibody is an anti-human CD15 antibody.
 75. The composition of claim 49, wherein the concentration of said anti-CD15 antibody is about 0.1 mg/l to about 15 mg/l.
 76. The composition of claim 49, wherein said anti-CD15 antibody is substrate-bound.
 77. The composition of claim 50, wherein said anti-CD9 antibody is a monoclonal antibody.
 78. The composition of claim 50, wherein said anti-CD9 antibody is an IgM antibody.
 79. The composition of claim 50, wherein said anti-CD9 antibody is an IgG antibody.
 80. The composition of claim 50, wherein said anti-CD9 antibody is an anti-human CD9 antibody.
 81. The composition of claim 50, wherein the concentration of said anti-CD9 antibody is about 0.1 mg/l to about 15 mg/l.
 82. The composition of claim 50, wherein said anti-CD9 antibody is substrate-bound.
 83. A kit comprising a blood collection vessel and a cell separation composition, said cell separation composition comprising: a) dextran; b) anti-glycophorin A antibody; and c) a substrate-bound antibody against a cell surface antigen of a human cell.
 84. The kit of claim 83, wherein said blood collection vessel is a blood bag.
 85. The kit of claim 83, wherein said blood collection vessel is a vacuum tube.
 86. A method for separating cells, said method comprising: a) contacting a blood cell-containing sample with a composition, said composition comprising: i) dextran; ii) anti-glycophorin A antibody; and iii) a substrate-bound antibody against a cell surface antigen. b) allowing said sample to partition into an agglutinate and a supernatant phase; and c) recovering said cells.
 87. The method of claim 86, wherein said sample is derived from a human.
 88. The method of claim 87, wherein said sample is a peripheral blood sample.
 89. The method of claim 87, wherein said sample is an umbilical cord sample.
 90. The method of claim 87, wherein said sample is a bone marrow sample.
 91. The method of claim 87, wherein said cells are metastatic tumor cells.
 92. The method of claim 87, wherein said cells are recovered from said supernatant phase.
 93. The method of claim 92, wherein said cells are stem cells. 